The present invention relates generally to wireless networks, and more particularly to access points for use in wireless networks.
In recent years, wireless networks have become increasingly popular. For example, networks including wireless mobile terminals now serve to help automate and expedite processes in retail, manufacturing, warehousing and other industries. In a retail environment, wireless mobile terminals may take the form of a wireless bar code reading device for use in tracking inventory and checking prices. In the warehousing industry, the same mobile terminals may be used to keep accurate accounting of incoming and outgoing shipments. In health care, transportation and other industries, the mobile terminals may take the form of wireless pen based computers to aid with on-site document control procedures, etc.
In order to provide for real time communication, the mobile terminals often include a radio which allows them to communicate with a host computer connected to a LAN, for example. LANs typically allow for connecting of devices operating in a building or specified site. Devices physically connected to the LAN may include desk top computers, printers and host computers. If the LAN also supports wireless mobile terminals such as those mentioned above, the LAN will also have connected thereto one or more access points (sometimes referred to as base stations). Each access point is coupled to the LAN and includes at least one radio through which wireless communication with the mobile terminals can occur.
Each access point can communicate with mobile terminals operating within the cell coverage area of the access point. The cell coverage area is the area in which the access point can reliably communicate with a mobile terminal. Once the mobile terminal roams outside of the cell coverage area of the access point, the mobile terminal can no longer communicate with the LAN through that particular access point. In order to provide cell coverage throughout an entire building or site, a LAN typically includes multiple access points strategically located throughout the building or site. Thus, the combined cell coverage of the access points is sufficient to cover the entire building or site. Mobile terminals may then roam from one area to another within the LAN.
Access points are known which include two radios for improving the reliability of a given wireless LAN. For example, U.S. Pat. No. 5,546,397 to Mahany describes an access point which includes two radios. In a first mode of operation, both radios operate on the same channel to create dual radio diversity. According to a second operating mode, the additional radio serves to monitor transmissions from other access points to confirm proper operation. In a third operating mode, the additional radio in two or more access points form a wireless bridge therebetween in the event of break in the network hardwired infrastructure.
Nevertheless, these conventional access points failed to address many non-reliability related problems. For example, such access points did not provide for simultaneous communications with two or more mobile terminals on respective channels.
Accordingly, there is a strong need with the art for an access point which provides for simultaneous communications with two or more mobile terminals on different channels. Moreover, there is a strong need in the art for an access point which carries out simultaneously different communication functions among the mobile terminals using respective radios. Finally, there is a strong need in the art for an access point which provides flexibility in operation based on the use of two or more radios.
In accordance with particular aspect of the invention, an access point is provided for use in a wireless network having a system backbone and a plurality of mobile terminals. The access point includes a communication circuit coupling the access point to the system backbone, and a first transceiver for wirelessly communicating with at least one of the plurality of mobile terminals on a first communication channel. In addition, the access point includes a second transceiver for wirelessly communicating with at least another of the plurality of mobile terminals on a second communication channel different from the first communication channel.
According to another aspect of the invention, a communication method is provided in a system comprising a system backbone, a mobile terminal, and an access point coupled to the system backbone for enabling wireless communications between the mobile terminal and the system backbone via the access point. The access point includes a first transceiver for communicating wirelessly via a first frequency hopping sequence, and a second transceiver for communicating wirelessly via a second frequency hopping sequence different from the first frequency hopping sequence. The method includes the steps of at least one of the first transceiver and the second transceiver broadcasting a beacon including hopping sequence data respectively corresponding to the first frequency hopping sequence or the second frequency hopping sequence; the mobile terminal responding to the beacon by transmitting to the access point a request to register; and the access point selectively permitting registration of the mobile terminal with at least one of the first transceiver and the second transceiver in response to the request to register, based on a predetermined criteria.
According to yet another aspect of the invention, a communication method is provided in a system including a system backbone, a mobile terminal, and an access point coupled to the system backbone for enabling wireless communications between the mobile terminal and the system backbone via the access point. The access point includes a first transceiver for communicating wirelessly via a first frequency hopping sequence, and a second transceiver for communicating wirelessly via a second frequency hopping sequence different from the first frequency hopping sequence. The method includes the steps of at least one of the first transceiver and the second transceiver broadcasting a beacon including hopping sequence data corresponding to both the first frequency hopping sequence and the second frequency hopping sequence; the mobile terminal selecting which of the first transceiver and the second transceiver to register with based on the hopping sequence data and responding to the beacon by transmitting to the access point a request to register; and the access point permitting registration of the mobile terminal with at least one of the first transceiver and the second transceiver in response to the request to register.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.